I have a report that contains 10 parameters of a same column name "def_prt".I am using in operator in this report for example.

select count(a.wc_id),b.def_prt
from sv_warr a,def_mst b
where a.prt_cd=b.prt_cdand b.gr_desc in (nvl(:prt_1,b.gr_desc), **Problem area**nvl(:prt_2,b.gr_desc),
nvl(:prt_3,b.gr_desc))
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when i remove all 10 parameter then the output shows all defective parts that is ok but if i select more than one parameter then only 1st input parameter defective parts display instead of all input parameter.